Our fast-paced, sedentary lifestyles and high-fat Western diets are putting more and more people at risk for diabetes mellitus (DM). Although the condition impacts the body in various ways, some of the more life-altering changes are those that affect our vision.
Our fast-paced, sedentary lifestyles and high-fat Western diets are putting more and more people at risk for diabetes mellitus (DM). Although the condition impacts the body in various ways, some of the more life-altering changes are those that affect our vision.
Diabetes mellitus causes abnormal changes in our blood sugar levels. Your body usually converts sugar into energy to fuel itself. Uncontrolled diabetes causes high levels of blood sugar to gather in blood vessels, which damages them, slowing blood-flow to various organs, including the eye.
Diabetes is classified as Type 1 or Type 2. Type 1 diabetes, also called insulin-dependent, needs injections or other medication to supply the insulin the body can't produce on its own. Type 2 diabetes is called non-insulin-dependent or insulin-resistant.
With this type, although the body can produce insulin, it has trouble using it properly and so continuously produces more. In both types, abnormal spikes in blood sugar increase the risk of diabetic retinopathy.
The most important risk factor for diabetic retinopathy (DR) is how long you've been diabetic. If diagnosed before 30, your risk for DR after 10 years would be roughly 50%. After 30 years almost all diabetic patients have some form of DR. People with insulin-dependent diabetes are at higher risk for DR than Type 2 diabetics.
High blood pressure or renal disease means increased risk for developing DR. It is thus wise to try and keep your sugar levels as stable as possible, especially when you have multiple risk factors. How the damage is done Diabetes affects the structural stability of the blood vessels in the eye, while simultaneously changing the various components of the blood itself.
Blood becomes sticky and the vessels weaken and start leaking proteins and lipids. Microaneurysms (localized weak spots in blood vessels) start forming and various small bleeds can start appearing in the eye.
Depending on where these bleeds, swelling and deposits form in the eye, the vision might be relatively good until later in the disease's progression. This is classified as preproliferative diabetic retinopathy (PPDR). All these changes contribute to less blood reaching the tissue, which receives less and less oxygen.
As a result, new abnormal blood vessels can start growing on different areas of the eye. This is a natural response from our bodies to try and save the “starving” tissue by getting blood to them. Normally this would be a good idea – but these blood vessels are very weak and can bleed into the eye.
On top of that they are usually found in places where we would rather not have them. When these abnormal blood vessels first start appearing, diabetic retinopathy is usually classified as Proliferative Diabetic Retinopathy (PDR).
Patients with PDR are at risk for serious bleeds and even retinal detachments. Depending where the blood vessels start growing, patients can also develop neovascular Glaucoma (increased pressure in the eye) causing secondary problems.
Symptoms
Symptoms can vary considerably. In most cases vision will slowly start deteriorating, even with the help of glasses. In other cases you might not notice any changes until very late in the progression of the disease.
Sometimes a patient might notice small black 'holes' in their vision, distortion, or 'spiderwebs'. In a severe retinal bleed there might be sudden, painless vision loss.
Prevention
The most important thing is to have regular eye examinations by an ophthalmologist or optometrist to evaluate the changes at the back of the eye. When changes are severe you might need to have laser treatment to 'burn' the areas of the vessels that are leaking or causing the bleeds. Laser treatment stops the progression of DR, preventing further loss of vision and even blindness. It seldom cures the condition or repairs vision already lost.
Visual fields are sometimes affected after laser treatment, which might affect activities such as driving. Depending on the severity and diagnosis, an eye specialist might also consider surgery or injections to remove the new blood vessels, or stop them from growing.
Moderate to severe changes in the eye, detected during an optometrist's regular examinations, might need to be referred to an eye specialist. The earlier diabetic retinopathy is diagnosed, the sweeter the outcome.
